The invention relates to tensioners, and more particularly to tensioners wherein the pulley comprises an inner race rotation pulley.
Transmission of power by belt can be accomplished by a driver pulley and a single or series of driven pulleys about which a belt is trained. It is occasionally necessary for the belt to change direction as it operates between a driver pulley and a driven pulley in order to clear other components. In this case, the belt can be trained over idlers that allow the belt direction to be changed with minimal loss of efficiency. For tensioning the belt, automatic tensioners may be used. In such case, the idler pulley is installed on the tensioner pivot arm.
Idlers generally comprise a base that is mounted on a non-rotating surface. The belt bearing surface or pulley is then rotatably connected to the base by means of a bearing. The bearing may be a ball bearing type having an inner and outer race. In most arrangements, the inner race of the ball bearing is attached to the idler base or to the non-rotating mounting surface directly. The idler pulley is then attached to the outer race of the ball bearing. The outer race and the pulley rotate together.
It is also possible to attach the pulley to the inner race of the ball bearing, with the outer race being fixedly attached to a mounting surface.
Representative of the art is U.S. Pat. No. 5,421,788 to Toth which discloses a belt tensioner having an idler pulley and bearing assembly. The idler pulley and bearing assembly comprise a non-rotating outer race and a pulley shaft extending through an inner race. The pulley is fitted to the inner race by means of the shaft, which shaft is pressed together with a retaining cup to hold the pulley shaft within the bearing inner race. Bearing lubricant is placed in the cup.
What is needed is an inner race, idler pulley tensioner having an inner race idler pulley with a self-lubricating bearing. What is needed is an inner race idler pulley tensioner wherein the pivot points are contained with in a periphery of the pulley. The present invention meets these needs.
The primary aspect of the present invention is to provide an inner race idler pulley tensioner having an inner race idler pulley with a self-lubricating bearing.
Another aspect of the present invention is to provide an inner race idler pulley tensioner wherein the pivot points are contained with in a periphery of the pulley.
Other aspects of the invention will be pointed out or made apparent by the following description of the invention and the accompanying drawings.
The invention comprises a tensioner having an inner race rotation idler pulley. The pulley having a web and a belt bearing surface connected to the web. The web is attached to an inner race of a bearing by a fastener. The pulley may be stamped out of sheet metal and may have a central hole for alignment with the central axis of the bearing. The outer race of the bearing is mounted to a pivot arm. The pivot arm comprises as least two pivot points for pivotably attaching the pivot arm to a mounting plate and a biasing member. The pivot point shafts are contained within a periphery of the pulley. The biasing member urges the pivot arm and pulley against a belt to be tensioned.